wilc1000: Remove duplicate struct declaration

struct wilc is declared twice. One has been declared
at 352nd line. Remove the duplicate.
Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210331023557.2804128-3-wanjiabing@vivo.com

drivers/net/wireless/microchip/wilc1000/wlan.h

@@ -398,7 +398,6 @@ struct wilc_cfg_rsp {
 	u8 seq_no;
 };
 
-struct wilc;
 struct wilc_vif;
 
 int wilc_wlan_firmware_download(struct wilc *wilc, const u8 *buffer,